1. Field
Example embodiments relate to a laser module and a laser display employing the laser module. More particularly, example embodiments relate to a laser module allowing direct light modulation by combining an external cavity laser with a non-linear optical element and a laser display employing the laser module.
2. Description of the Related Art
Conventionally, to create visible light having a relatively low power of about 107 mW, a Distributed Feedback (DFB) or Nd:YAG laser is used to generate infrared (IR) light. The IR light is then coupled to a periodically-poled second harmonic generation (PP-SHG) material.
However, a complicated optical system is typically required to couple a 1060 nm DFB laser into an SHG waveguide at least because the 1060 nm DFB laser has a large divergence angle and an asymmetric optical profile. Thus, the laser becomes bulky and relatively large coupling losses tend to occur. Furthermore, if the 1,060 nm DFB laser is used for direct light modulation, the direct light modulation generally cannot be practically and/or effectively achieved because (i) the wavelength of optically modulated light is generally not uniform due to its thermal instability and (ii) IR light of a wavelength of about 1,060 nm generated by a DFB laser has a relatively low output power.
Further, an Nd:YAG laser generally cannot achieve direct light modulation because an Nd:YAG laser generally has a very low modulation speed.
Conventionally, because neither a DFB laser nor a Nd:YAG laser can achieve direct light modulation without an Acousto-Optic Modulator (AOM) and an AOM driving circuit, an AOM and AOM driving circuit are used and/or required if the DFB or Nd:YAG laser is used in a display requiring optical intensity modulation. The use of the AOM and AOM driving circuit causes difficulties when it comes to providing compact displays.